<!DOCTYPE html>
<html>
  <meta charset="utf-8">
  <link rel="author" title="Ting-Yu Lin" href="mailto:tlin@mozilla.com">
  <link rel="author" title="Mozilla" href="https://www.mozilla.org/">

  <style>
  @page { size: 5in 3in; margin: 0.5in; }
  body { margin: 0; }

  .flexbox {
    border: 0.25in solid black;
    font-size: 0.25in;
  }
  .item {
    contain: size;
    box-sizing: border-box;
    border: 4px solid purple;
    height: 0.5in;
  }
  .gap {
    height: 0.2in;
  }
  </style>

  <!-- This div makes the flexbox not at the top of first page. -->
  <div style="height: 0.25in; background: gray;"></div>

  <div class="flexbox">
    <div class="item">1</div>
    <div class="gap"></div>
    <div class="item">2</div>
    <div class="gap"></div>
    <div class="item">3</div>
    <div class="gap"></div>
    <div class="item">4</div>
    <div class="gap"></div>
    <div class="item">5</div>
    <div class="gap"></div>
    <div class="item">6</div>
  </div>

  <div style="height: 0.25in; background: gray;"></div>
</html>
